The Naval Electrical Engineering Training Series(NEETS)
Here's the link to the section on tubes. Easy to understand, and pretty thorough.
Neets Module 06-Introduction to Electronic Emission, Tubes, and Power Supplies
Hi. I have played a lot with solid state diy, but have absolutely no experience with tube stuff. I have bought an old Musical Fidelity Nuvista DAC with a tube output stage, and since it is some 15 years old, I decided to change the electrolytic capacitors before they began leaking. I started with the PSU, replacing all electrolytics with the same values. After that the 4x100 volt capacitors will give me an electric chock, if I touch the metal bottom of the capacitor and the chassis simultaneusly. I have never worked with a 100v capacitor before, but is that normal or did I forget a ground connection somewhere ???